docstr: Returns the xpos tags known by this model
docstr_tok: ["Returns","the","xpos","tags","known","by","this","model"]
code: def get_known_xpos(self):
      """
      Returns the xpos tags known by this model
      """
      if isinstance(self.vocab["xpos"], CompositeVocab):
          if len(self.vocab["xpos"]) == 1:
              return [
                  k
                  for k in self.vocab["xpos"][0]._unit2id.keys()
                  if k not in VOCAB_PREFIX
              ]
          else:
              return {
                  k: v.keys() - VOCAB_PREFIX
                  for k, v in self.vocab["xpos"]._unit2id.items()
              }
      return [
          k
          for k in self.vocab["xpos"]._unit2id.keys()
          if k not in VOCAB_PREFIX
      ]
  
file_path: stanza/stanza/pipeline/pos_processor.py
imports: import torch
  from stanza.models.common import doc
  from stanza.models.common.utils import unsort
  from stanza.models.common.vocab import VOCAB_PREFIX, CompositeVocab
  from stanza.models.pos.data import Dataset
  from stanza.models.pos.trainer import Trainer
  from stanza.pipeline._constants import *
  from stanza.pipeline.processor import UDProcessor, register_processor
  from stanza.utils.get_tqdm import get_tqdm
label_desc: Use image node_id 3 for calling the POSProcessor obj's underlying member method code with example usage: obj.get_known_xpos() and returns: unknown, unknown, unknown